Boating and water sports pose some unique risks to children, primarily because they combine all the normal risks of drowning with both speed and deeper waters. For example, when you wakeboard, your body can travel at up to 40 m.p.h., can hit the water with 3,000 pounds of force, and, lacking a life jacket, a person's body would sink in 5 seconds. A child would disappear in seconds and be on their way to the bottom before the boat could even turn around in such an accident. When you combine deep water with high speeds, disastrous things can happen.
There is really only one all-important boating / water recreation safety rule for kids: wear a life jacket. The U.S. Coast Guard estimates that life jackets could prevent approximately two-thirds of all boating-related drowning deaths in children ages 14 and under. So always have kids wear a personal floatation device when boating or doing other water recreation sports, even if they are otherwise good swimmers.